[Music] med.com welcome to another medc video today we're going to talk about a paper that just came out that really answers the question about where you ought to be spending your time if you want to avoid cancer and the risk factors this was published in the flagship Journal of the American Cancer Society cancer a cancer journal for clinicians and the title of the study is proportion and number of cancer cases and deaths ATT tributal to potentially modifiable risk factors in the United States in 2019 this is actually taking it up until the pandemic and looking at the risk factors during this time before 2020 and asking first of all what are the risk factors and how many cases of cancer can be attributable to these risk factors and I think this is a really good exercise to look at in school you remember when you got lectures and you're like okay what should we be concentrating on what should we be learning about for the test well this is kind of that for cancer like what are the risk factors that we really need to look at in proportion because everything causes cancer it seems right but what are the things that are actually turning up and this paper goes into it pretty well I won't go through the methodology of it but there's a lot of interesting equations but let's take a look at what they found so first of all we're going to look at both sexes combined here and then we'll break it out there's actually not that big of a difference between the two the way you want to read this graph is first of all look at the Top Line it's looking at all the risk factors that they identified there's certainly other ones but the ones that they looked at here were the ones that they thought were the most attributable and when they looked through it and did the calculations what they found was 40% of all of the cancers in the United States were attributable to the risk factors that they list and then they go through and they actually list it out and folks it's quite sobering here because up to half of all of the cancers that are attributable to the risk factors are on this page is attributable to one specific risk factor and that is cigarette smoking you can actually see over here how many cases of cancer so it's not just lung cancer right so throat cancer is attributable to cigarette smoking a number of other cancers increase in cigarette smoking but here 344,000 were attributable to cigarette smoking and let's just go down and look at some of the other ones here excess body weight alcohol consumption UV radiation now we've talked a lot about light and we've talked about infrared light can actually penetrate through clothing it's available in the early morning hours and the late evening hours exactly when you really want to be going outside if you want to avoid UV radiation we're going to be talking about what they found in terms of light sunlight and things of that nature in future videos but we're just going to put that there on the board physical inactivity so exercise is really important and then we run into other things like HPV infections low fruit vegetables processed meat low dietary fiber hpylori infection red meat and then a bunch of other infections and look at this one even secondhand smoke pops back in again even secondhand smoke has an attributable risk this is for both sexes combined both male and female let's break it out and actually look at the different Sexes here here we have men you can see it's a more Stark situation with cigarette smoking so all risk factors once again about 40% of all cancers in the United States are caused by ATT tributal risk factors that are listed on this page right after cigarette smoking we have UV radiation and interesting men are typically outside more often we're going to talk about UV radiation and getting outside cuz we've advocated for getting outside we've been told multiple times that you can get too much sun exposure what we haven't heard is is it possible to get too little sun exposure and we've gone over the data that clearly sun exposure actually reduces cardiovascular disease and and things of that nature for instance in the southern Sweden study what we haven't talked about is some of the evidence in terms of sunlight and cancer we're going to talk about that in future lectures but notice here that they attribute ultraviolet radiation as pretty high risk factors predominantly for things like melanoma and other types of cancers excess body weight alcohol consumption low fruit vegetable intake physical inactivity processed meat red meat appears on here and again same sort of list it gets pretty low as we go down the list key here is cigarette smoking that's going to be the theme of today's talk let's take a look at women about 40% of all cancers in women are directly attributable to the risk factors listed on this page the biggest single one although lower in women is cigarette smoking interestingly something that's a little bit higher up than it was for men excess body weight alcohol consumption physical activity UV radiation a little bit further down on this list something that was a little bit higher up is HPV infection and that opens up the discussion about vaccination and cervical cancer which we'll talk about in terms of preventable cancers but once again we see low dietary fiber processed meat low fruit vegetable red meat and then we've got these infections going all the way down again the way to read this graph is these numbers here on the side are what percent of all of the cancers is this specifically causing so it gets pretty low here as you get down but of course the big one here is cigarette smoking in both male and female this is a different type of graph now instead of risk factors in this study what they looked at was the actual cancer so here at the top for instance we have cervical cancer and then we have something called carpos saroma and what they're listing out here is not which ones are the most common certainly not as you can see here these are fairly smaller numbers than what you would expect to see like for instance with cancer of the lung which is around 200,000 these are only about 12,890 so why are they way up here at the top this is asking what what percent of these cancers come from risk factors on the previous pages in other words which one of these are the most preventable so the ones here at the top are the most preventable because the percentages of these cancers are directly related to those attribut risk factors that we saw on the previous pages so for instance cervical cancer based on the data that they have is almost 100% preventable and there were some recent studies in the Nordic countries where they looked at vaccination for HPV and found that there was a close to 95 to 100% drop in cervical cancer so this is what they're basing this on carpos saroma is another one that's 100% preventable and if you go back here even though it doesn't cause a lot of these what you need to have for carpos saroma is a HIV infection and then a human herpes 8 infection together will cause carpos sarcoma if you don't have those or either of those you cannot get essentially carpos saroma so again here on this list we're not looking at the ones that are the most common we're looking at the ones that are the most preventable anal cancer melanoma of the skin I think they're making the case here that ultraviolet radiation and overuse of ultraviolet radiation specifically in tanning beds things of that nature can cause melanom in the skin now we start getting into the things of smoking cancer of the larynx that's throat cancer cancer of the bronchus that's lung cancer cancer of the ferx the trachea the esophagus is related to cigarette smoking the oral cavity is related to that and then the list goes on although not so much for smoking you can see that these here are very preventable cancers that are directly related to smoking and you can see some of the rest down here female breast cancer is very common they're saying here up to 30% or more is preventable based on the previous risk factors and they actually go through this in the article which I'll put a link to in the description below so let's go back to the original slide which again shows both sexes combined and the risk factors and here we clearly see that cigarette smoking is a big risk factor for lung cancer lung bronchus 88.2% of people who get lung cancer preventable so was related to smoking that means that there is a group of percentage here that didn't have this related to smoking and that's something that we're researching we're not here to pass judgment on people who smoke we're not trying to make them feel bad we're not trying to exclude them but it's important to educate on the dangers and if we can get them to quit smoking perhaps even a better life down the road now we've already talked about in some of our lectures what the effect is on the lung function in terms of COPD fev1 things of that nature if you want to learn more about that certainly check us out at medcram.com and you can check out our lectures on that topic but what is the effect of smoking on lung cancer and what can we do about it many of you may not know that there is an organization called the United States preventative Services Task Force which comes out with recommendations in terms of screening to prevent Lung Cancer let's take a look here at the lungs the lungs are a very squishy organ which means that things can grow in them very easily and you won't notice it until they get very big so if you've got a lung cancer that's growing you're not going to feel the effects of that until it gets so big that it's actually started to metastasize and spread and unfortunately the largest stage that we see at diagnosis is generally metastasis that's the way that it used to be very regularly so what you want to be able to do is to pick up these lung cancers before they spread because if you can get them when they're very small then you can actually cut them out and cure the patient of their lung cancer but you can't do that unless they are resectable tumors in other words they haven't already spread in other words you can't close the Barn Door after the horse has escaped out of the barn you want to catch it early the best way to do that is actually with something called a CT scan or specifically a lowd do CT scan when people go in and get an x-ray of their lungs and let's take a look at what that looks like here this image here on the left is a chest x-ray chest x-ray is very good for finding kind of gross things like pneumonia or a fusion but it's not very sensitive at finding tumors that are growing very small this would not be a good technique to screen for lung cancer and that's unfortunate because the amount of radiation associated with an x-ray is very very small and we would not be worried about giving radiation to people and causing cancers on a huge population basis what's much better at detecting nodules than chest de tray as you can see with this nodule here on the CT scan is a CT scan so a CT scan unfortunately is about roughly 500 chest x-rays in terms of radiation so if you're going to be screening a population looking for lung cancers you're almost undoubtedly going to be actually causing some lung cancers because you're giving that much radiation and so we're trying to in terms of a distribution of patients that are out there we're looking at those that are the highest risk for having lung cancer and those that are the lowest risk we're trying to find a good cut off line above which the benefits of screening out weighs the risks and Below which we're not going to be doing it because the risks of screening outweigh the benefits so what they've done is they've decided to make some guidelines about who these people are that are the highest risk so that we only screen these people to make it cost effective and to make sure that we're not causing excess lung cancers and instead of doing a regular CT scan they're doing something called a low dose CT scan and this means that in fact instead of 500 chest xray worth it's actually much much lower than that that even though you lose some of the resolution because you're not giving as much radiation you're still able to detect early the lung cancer so let's take a look and see what the screening criteria is this is from the United States preventative Services Task Force and it's based on evidence which they give as a Grade B so what they recommend actually is for anybody between the age of 50 and 80 years of age who have a 20 pack year smoking history and currently smoke or have quit within the last 15 years these are the people that are at highest risk for having lung cancer and should be getting annual lowd do CT screening there is one other caveat this screening should be done in people who could actually go through a surgery where they could have a portion of their lung taken out so if they have severe COPD for instance and they're on oxygen they're not going to be able to stand losing a portion of their lung and so this may not be the right thing for them again 50 to 80 20 pack year and what is a 20 pack year smoking history so that would be an example of somebody for instance who smoked one pack per day times 20 years another example would be someone that smokes two packs per daytimes 10 years just so you're aware a number of years ago they actually updated this recommendation it used to be 55 to 80 but they wanted to improve the screening and capture a wider population and this used to be instead of 20 pack year smoking history it was a 30 pack year smoking history they've actually included a wider population to screen from because they believe that this is actually saving lives and there's some studies that have actually shown this we won't get into today just because of brevity but you can look those up the studies is what gives this a Grade B recommendation when they looked at this so when patients come to see me this is one of the things that I actually look at I ask them if they're smoking when did they quit how many pack years do they have and how old they are and we have a discussion about the use of annual CT screening and I explained to them that this is something that they would have to do until either they turn 80 years of age or they've quit and it's been 15 years or if their lung function gets worse or they're unable to do it so this is a discussion that you have with your patients and decide whether or not this is something for them the point here is that if you find a nodule this is then going to set off a Cascade of events where you're going to have to see what that nodule is and what it's doing and that'll be the topic of another lecture where we give is what do you do with lung nodules that's something that we look at with the fler criteria we'll talk about that in a subsequent video but if you wanted to learn more about lung cancer I highly recommend you come to medcram.com where we talk about lung cancer explain clearly and exactly what are the epidemiology what's the diagnosis the treatments and how we manage patient and stagel as well patients with lung cancer again if you like this video please join us at medcram.com where we have continuing education units for Physicians nurses Nurse Practitioners Pas respiratory therapists pharmacists Etc this is medicine explained clearly if you like this video please subscribe turn on notifications leave us a comment and join us at medcram.com [Music]